"Once" opened on Broadway in March and received eight Tonys, including the prize for best musical. The album features actors Steve Kazee and Cristin Milioti. The original 2006 movie won an Oscar for original song.

Glen Hansard and Markéta Irglová, who starred in the "Once" film, are the composers and lyricists. The award is shared with Kazee and Milioti, as well as producers Steven Epstein and Martin Lowe.

Last year's Grammy winner for musical theater album was "The Book of Mormon."